Intebnal-combttstion engine and method fob opebating sake



Aug. 28, 1928. 1,682,305

L. G. NILSON INTERNAL COMBUSTION ENGINE AND METHOD FOR OPERATING SAMEFiled Sept. 27, 1921 2 Sheets-Sheet 1 a9 v [4 W 3 429 0 O 4 12-? P L?INVENTCR ATTORNEY Aug. 28, 1928.

L. G. NILSON INTERNAL COMBUSTION ENGINE AND METHOD FOR OPERATING SAMEFiled Sept. 27, 1921 2 Sheets-Sheet INVENTOR BY E ATTORNFY abstractingfrom the same the i Patented Aug. 28, 1928.

UNITED STATES LABS G. NILSON, OF HOBOKEN, NEW JERSEY.

INTERNAL-COMBUSTION ENGINE AND METHOD FOR OP EBA'II'NG BAKE.

Application filed September-27, 1921.

This invention relates to internal combustion engines and a method foroperating the same, and more particularly to a means for increasing thethermal efiiciency of such engines while lowerin the maximum pressure ofthe working flu1d therein. The operation of all internal combustionengines, whether reciprocating or rotary, and whether two or four cycle,consists in introducing a gaseous char e into a closed s ace, comressingthe ciarge, igniting it, a lowing the lgnited charge to perform workwhile expanding, and finally in exhausting the spent products ofcombustion. The gaseous charge may be a. combustible mixture, as inordinary engines, or it may be air into which liquid fuel is injected oncompression, as in engines of the Diesel type; the principle abovestated being ap licable in either case. The temperature an pressure ofthe charge immediatel after ignition are always excessive, an aregenerally recognized to be the cause of near y all the failings to whichinternal combustion engines are subject. The object of this invention isto reduce this excessive temperature and pressure, and to store theenergy which it represents and deliver this energy to the ex andinggases at a time when it can be in ly utilized; also to exhaust the spentgases at a lower temperature than otherwise possible, thereby eatestpossible amount of heat and increasing the thermal efliciency of theengine.

In carrying out my invention, I connect an auxiliary chamber with thecombustion space of the engine cylinder. Communication between thischamber and cylinder is controlled by means of a properly timed valve,which is closed at about the end of the working stroke and just beforethe exhaust valve opens. The spent gases are now exhausted and a freshcharge introduced into the cylinder. When this char e is compressed toabout the pressure 0 the gases within the auxiliary chamber,communication with the latter is now opened; the compression of thecharge is completed, ignition takes place, and the piston is drivenforward. It will be seen that when the charge is ignited, a portion ofits energy will go into heating and compressing the gases within theauxiliary chamber, rather than to heating and compressing the chargeitself to an excessive degree; and that during the working stroke thegases within the auxiliary Serial No. 503,549.

chamber will expand and do work uponthe piston, thus delivering the enerstored in them at the beginning of the stro e. As the initial ternerature of the ignited charge is lowered, t e exhaust temperature willbe lowered and the thermal efiiciency will be increased. By closincommunication between the auxiliary c der just before exhaust takesplace, the pressure of the gases trapped within the auxil- 1ary chamberwill be suflicient to maintain proger compresslonof the charge on reestal1sh1ng communication before completion of compression. In many casesthe effectlveness of my device may be increased by the addition of waterto the auxiliary chamber, thus absorbing heat at the beginning of theworking stroke and delivering the heat energy in the form of work to thepiston during the latter ortion of the stroke.

With these an other objects in view, I have devised the apparatusembodying my invention, as described in the following specification, andillustrated in the accompanying drawings, of which Figure 1 is a sideelevation, mainly in section, of the device attached to an internalcombustion engine,

Fig. 2 is a diagrammatic representation of the events occurring in thecycle of the engine,

Fig. 3 is an indicator card diagram,

gig. 4 shows a modified form of valve, an

Fig. 5 shows a further modification in the form of valve.

Fig. 6 is a section taken on the line X Y of 5.

Re erring to the drawing, 1 represents the cylinder of an internalcombustion engine, having intake and exhaust valves 2 and 3respectively. Piston 4, reciprocating within cylinder 1, drives crank 5and shaft 6 through connecting rod 7. An opening 8, communicating withcombustion space 9, is provided in cylinder 1; and attached to cyllnder1 by flanges or other suitable means is auxiliary chamber 10, having itsinterior communicating with opening 8. Between the interior of chamber10 and combustion space 9 is a valve 11, actuated by cam 12 through link13, bell crank 14 attached thereto, and link 15 connecting bell crank 14and valve 11. Cam 12 is keyed or otherwise securely fixed to cam shaft16, driven by gears amber and the cylin 17 and 18 from crank-shaft 6. Ina four cycle engine the r ratio is such that shaft 16 makes one revoution to every two of shaft 6. In many engines the ordinary valve timingcam shaft ma be utilized for this purpose. Link 19, pivoted as at 20,holds cam roller 21 to which it is attached, from lateral or tan entialmovement, and link 13 maybe pivoted to link 19 or connected directlywith roller 21. The movement of valve 11 may be advanced or retarded byrotating pivot oint 20 about the axis of cam shaft 16, by

over 22 ivoted on said axis and carrying pivot point 20; lever 22 belngclamped in any desired setting by nut 23 and bolt 24 in sector 25.

Water is introduced into chamber 10 by pipe 26 leading from pump 27having entrance and discharge valves 28 and 29 respectively, valve 28being supplied from reservoir 30 by pi e 31. Plunger 32 of ump 27 isactuate on its working stroke by rod 33', driven through roller 34 andcam 35 by shaft 36. Plunger 32 is returned by spring 37. Wedge 38,interposed between rod 33 and plunger 32, controls the eilectlve lengthof rod 33, and thus by its positlon determines the length of stroke ofplunger 32. Adjustment of wedge 38 is effected through crank 39 securedto shaft 40, which may be rotated either manually or by a governorcontrolled device. Water injection is made preferably in timed relationto the stroke, and in such cases shaft 36 may be identical with shaft16, being shown separate merely for convenience of representation. Cam35 is set to deliver the water immediately after the closing of valve11, thereby allowing maximum time for the generation of steam in chamber10.

In Fig. 4 is shown a modification in which rotary (or oscillating) valve41 is substituted for slide valve 11. Valve 41 is actuated by shaft 42carrying crank arm 43,

a which may be directly attached to lever 13.

In Figs. 5 and 6 is shown a modification in which poppet valve 44 issubtituted for slide valve 11. Valve 44 is clamped to arm 45 to providefor proper seating, while arm 45 has a hub portion keyed on, orotherwise rigidly secured to, shaft 47 passing through the latter. Arm48, fixed to shaft 47, is pivoted to yoke 49 carrying sleeve 50 throughwhich passes rod 13. Secured to rod 13 is collar 51, and between thelatter and the end of sleeve 50 is compression spring 52.. Adjusting andlock nuts 53 and 54 respectively on the end of rod 13 maintain spring 52in suitable compression. Spring 52 will take up any slight inaccuracy inthe throw of crank arm 48 in seating valve 44. Shaft 47 has a shoulder55 which, to ether with the end of bushing 56 through wfiich shaft 47passes, constiutes a ground joint to prevent loss of pressure. Shoulder55 should, of course, be of small enough diameter to pass through theopening into which bushlng 56 fits, thus facilitatin assembl Thisarrangement is preferable to astu ng box in cases where the temperaturewould injure ordinary packing.

In any of the above described forms,

-"chamber 10 may be made in two flanged parts, as shown in Figs. 5 and6, to facilitate access to valves 11, 41 or 44 for grinding or forassembling.

l/Vater jacketing 57 may be provided about valves 11, 41, or 44, asshown in Figs. 4 and 5. Chamber 10 is elsewhere blanketed withinsulating material as at 58, to conserve all the heat possible.bylinder 1 may be cooled by any suitable means.

The operation of the device for a four cycle engine will be consideredin relation to Figs. 2 and 3. The reference points of the former aretaken on radii corresponding to the various angular positions of crank5, assuming clockwise rotation; while the reference points of the lattercorrespond, with respect to their abscissas, to the various positions ofpiston 4. The ordinates of the points on Fig. 3 represent the pressureper unit area of the working fluid, and the dotted line represents thepressures during the working stroke when using the auxiliary chamber, ascontrasted with the pressures on ordinary engines represented by thesolid line. Points represented by the same letter on either diagramrepresent identical phases. The point A represents the beginning of theintake stroke. Piston 4 is at the beginning of its stroke; crank 5 is oninner dead center; intake valve 2 is in the act of opening; exhaustvalve 3 has just closed. Cam 12 is so designed and so set that at thispoint valve 11 will be closed. Piston 4 now moves to outer dead centerand begins its return stroke; intake valve 2 is closed at or about pointB, and compression of the charge begins. When the compression stroke isabout three-quarters complete, or at about the point where the pressureof the ases within chamber 10 will just about equfi the pressure of thecharge in cylinder 1, valve 11 is opened. This point is indicated by G.Piston 4 continues its inward stroke and ignition is effected at pointD, at or before crank 5 reaches inner dead center at C. The flame,travelling away from the spark plug and gaining in intensity, instead ofdelivering a hammer blow to the piston, de-

loo

livers a portion of its energy to the gases in into more advantageouspositions for converting pressure into torque at the crank charge at theopening of va ve 11 is about equal to the pressure of the gases justbefore the opening of exhaust valve Qarn 12 is designed and set withthat end 1n view, so that the opening of valve 11 Wlll not lower thecompression. As the charge is further compressed, a small amount willenter chamber 10, but will not have time to diffuse and mingle with thespent gases therein, and Whatever slight mixlng does take place in noway serves to hamper complete combustion. As ignition takes place. acertain amount of the pressure and heat resulting therefrom will go tocompress and heat the gases in chamber 10, and the sharp ressure peakshown by the solid line in ig. 3 will be avoided. But while the initialpressure is less, the fall of pressure as the cylinder volume increaseswill also be less, as the quantity of working fluid is now increased bythe contents of chamber 10, and the dotted line will cross the solidline and indicate a higher mean eifective pressure. Regarded from thestandpoint of thermal efiiciency, it will be ap arent that the exhaustgases will be release at a lower temperature, because the excessiveinitial temperature has been reduced. Much of the heat absorbed by thecooling water and otherwise dissipated during the excessive initialtemperature will also be saved, as such heat losses are directlyproportional to the temperature diiference between the burning mixtureand the walls of the combustion chamber and cylinder. It is generallyconceded that the greatest amount of wall loss occurs in the early partof the stroke, when the pressure and temperature are at maximum, and thepiston speed is comparatively slow.

In Fig. 3 the upper solid line represents a typical and practicalexpansion curve in an ordinary engine without the auxiliary chamber. Thedotted line just above this curve indicates a practical and typicalexpansion curve such as would be obtained from an engine using theauxiliary chamber in the manner described.

Not only will the application of the device increase the efliciency ofthe engine, but, by eliminatin the excessive maximum pressure shown in*ig. 3, mechanical strains upon the wrist pin, crank bearings, etc.,will be avoided, resulting in a smoother running engine, and permittinglighter construction; while by eliminating the excessive maximumtemperature, cylinder lubrication will be facilitated. The lowering ofthe maximum temperature, and the raising of the mean effective pressurepermit the development of power at a slower piston speed. This isespecially advantageous for marine work. Liability to knocking, heating,breakage and similar evils will be almost entirely avoided.

By injecting'water into chamber 10 in the manner described, theeffectiveness of the latter will be increased in many cases, due to theabsorption of heat by the steam and return of this energy to the pistonduring the working stroke in the form of ressure. The workingtemperature wil be lowered and formation of carbon prevented.

While the above detailed explanation of the operation of the inventionis made in connection with a four cycle reciprocating engine, it isclear that the invention may be applied to any type of internalcombustion engine. On a two cycle engine there would be no reductionbetween gears 17 and 18.

Instead of the injection of water, as above described, into chamber 10,I consider also the injection of certain gases to be advantageous undercertain conditions, especially in reducing temperature, and theinjection of air, water, steam or other inert volatile substance or gasI consider within the scope of my invention.

What I claim is:

1. The combination with an internal combustion engine provided with a.cylinder, piston, and means for supplying the fuel to and exhaustingsaid cylinder, of a closed chamber connected with the engine cylinderadjacent the combustion space, a valve for closing said chamber fromcommunication with said cylinder, and means for closing said valve Justbefore the products of combustion are exhausted from said cylinder andfor opening said valve just before ignition occurs.

2. The combination with an internal combustion engine provided with acylinder, piston, and means for supplying the fuel to and exhaustingsaid cylinder, of a closed chamber connected with the engine cylinderadjacent the combustion space, a valve for closing said chamber fromcommunication with said cylinder, and means for closing said valve justbefore the products of combustion are exhausted from said cylinder andfor opening said valve before ignition at substantially the samepressure at which said valve was closed.

3. The combination with an internal combustion engine provided with acylinder, piston, and means for supplying the fuel to and exhaustingsaid cylinder, of a closed chamber connected with said engine 0 linderadjacent the combustion space and 0 a size adapted to reduce theignition pressure a substantial amount and yet return absorbed heat tosaid cylinder during'its power stroke, a valve for cutting off saidchamber from communication with said cylinder, and a mechanism forclosing said valve after the engine has completed at least a substantialportion of its power stroke and for opening the same just beforeignition occurs.

4. The combination with an internal combustion engine provided withcylinders, pistons, and means for supplying fuel to and exhausting saidcylinders, of means for removing from a cylinder at ignition apredetermined portion of the charge to reduce the pressure as ignitionoccurs, heat insulated means for holding said charge, and

mined means permitting the (passage of a redeterortion of sai extracted0 arge to a cylin er during the major portion of the power strokethereof.

5. The combination with an internal combustion engine provided withcylinders, pistons, and means for supplying fuel to and exhausting saidcylinders, of means for removing a predetermined portion of the productsof combustion from a cylinder just before exhaust occurs, and means forplacing said removed portion of the combustion products in communicationwith the charge in a cylinder during the compression stroke thereof, andbefore ignition occurs.

Signed at New York, in the county of Hudson and State of New Jersey,this 26th day of September, A. D. 1921.

LARS G. NILSON.

